Question

Вычислить концентрацию гидроксильных ионов, если pH=5?

Answer 1

pH+pOH=14  

Т.к. [H+][OH]=10-14 ,  то[OH]=10-14:[H=]=10-14:10-5=10-9моль/л

 

Answer 2

Calculating Hydroxide Ion Concentration from pH

To calculate the concentration of hydroxide ions (\(OH^-\)) from the given pH value of 5, we can use the formula:

\[ pH = -\log[H^+] \]

Where \( [H^+] \) represents the concentration of hydrogen ions in moles per liter. From this, we can calculate the concentration of hydroxide ions using the relationship:

\[ [H^+] \times [OH^-] = 1.0 \times 10^{-14} \]

Let's proceed with the calculation.

Calculation

Given: pH = 5

Using the formula \( pH = -\log[H^+] \), we can solve for \( [H^+] \):

\[ -\log[H^+] = 5 \]

\[ [H^+] = 10^{-5} \]

Now, we can use the relationship \( [H^+] \times [OH^-] = 1.0 \times 10^{-14} \) to find \( [OH^-] \):

\[ 10^{-5} \times [OH^-] = 1.0 \times 10^{-14} \]

\[ [OH^-] = \frac{1.0 \times 10^{-14}}{10^{-5}} \]

\[ [OH^-] = 1.0 \times 10^{-9} \]

Answer

The concentration of hydroxide ions (\(OH^-\)) when the pH is 5 is 1.0 x 10^-9 moles per liter.